OBSERVATION OF NEUTRAL HYDROGEN IN THE GLOBULAR-CLUSTER NGC-2808

We have used the Parkes 64 m-reflector of the Australia Telescope National Facility to observe globular clusters in the 21 cm line. In the direction of NGC 2808, we have detected H I emission with the following characteristics: (1) the peak of the spatial distribution is located on the cluster's center; (2) the peak of the velocity distribution matches the cluster's published radial velocity of 98 km s-1 to within its quoted uncertainty of 4 km s-1; and (3) the FWHM of the H I profile is consistent with the cluster's published stellar velocity dispersion and escape velocity. The characteristics of this emission are very suggestive of its being due, at least in part, to gas which is physically associated with the cluster. This is not beyond dispute, however, since there is known to be an extended region around the cluster exhibiting foreground 21 cm emission at about the cluster's radial velocity. If further observations confirm that the emitting gas is intrinsic to NGC 2808, this would constitute the first significant detection of H I within a globular cluster.